As disclosed in International Patent Application WO 93/13188 (Sabahi) and U.S. Pat. No. 5,399,279 (Sabahi et al.), oily Michael addition products of the dialkyl malonate/alkyl acrylate type are known to have general utility as lubricants and to be particularly valuable for use as lubricants in compositions containing fluorohydrocarbon refrigerants. Various conventional additives can be used in conjunction with these ester oil lubricants, but it would be desirable to find other additives capable of improving their lubricity without having an unduly deleterious effect on their miscibility with fluorohydrocarbon refrigerants.